10 Gallon need helping adding new fish

This is a discussion on 10 Gallon need helping adding new fish within the Beginner Freshwater Aquarium forums, part of the Freshwater Fish and Aquariums category; -->
Hello,
I am currently in the process of changing up my established 10-gallon aquarium.
Currently I have 3 rasboras along with 1 guppy that ...

Hello,
I am currently in the process of changing up my established 10-gallon aquarium.
Currently I have 3 rasboras along with 1 guppy that have been together for almost a year.
I will be taking out the dying live plants, and don't plan on adding new live plants unless necessary, but would consider a moss ball if that helps.

I am looking to get a bottom dwelling fish that can be kept without others of its species, something that would take advantage of the little cave I have set up in the tank.

I may also be changing from gravel to sand if that fits better for the fish.
Also, does anyone know if placing a seashell from the beach into the aquarium would be a bad idea?

Plants are always beneficial. A 10g tank is only going to be suited for fish that will be better if surrounded by plants, so I would strongly consider these. We can discuss the present plant problem, which could be light, filtration, nutrients, type of plants, individually or together.

Substrate fish are limited in a 10g. The dwarf species of cory in a group of 7-9, one Whiptail Catfish, or as an alternative shrimp. For upper fish, there are many dwarf species among the cyprinids, and a few others. Knowing the water parameters would help narrow these down, but most are soft water fish. Check the profiles, second tab from the left in the blue bar across the top of the page.

Sand substrate will be good for any of what I've mentioned, including plants.

To answer the seashell question, I personally wouldn't do it. I would worry about it affecting water chemistry - I have always been under the impression that shells can impact the hardness of the water. Anyone care to confirm or deny that?

Correct. Shells are calcium, and they dissolve in water, so this will increase the hardness and corresponding pH. Of course the initial GH and pH as well as the water volume and the number of shells all factor in. But if for instance the basic GH/pH is close to the upper limit for the fish species, adding a shell could cause more trouble than it would in a hard water tank with fish needing hard water.